Dissertations / Theses on the topic 'N-type solar cells'
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Chen, Wan Lam Florence Photovoltaics & Renewable Energy Engineering Faculty of Engineering UNSW. "PECVD silicon nitride for n-type silicon solar cells." Publisher:University of New South Wales. Photovoltaics & Renewable Energy Engineering, 2008. http://handle.unsw.edu.au/1959.4/41277.
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The cost of crystalline silicon solar cells must be reduced in order for photovoltaics to be widely accepted as an economically viable means of electricity generation and be used on a larger scale across the world. There are several ways to achieve cost reduction, such as using thinner silicon substrates, lowering the thermal budget of the processes, and improving the efficiency of solar cells. This thesis examines the use of plasma enhanced chemical vapour deposited silicon nitride to address the criteria of cost reduction for n-type crystalline silicon solar cells. It focuses on the surface passivation quality of silicon nitride on n-type silicon, and injection-level dependent lifetime data is used extensively in this thesis to evaluate the surface passivation quality of the silicon nitride films. The thesis covers several aspects, spanning from characterisation and modelling, to process development, to device integration. The thesis begins with a review on the advantages of using n-type silicon for solar cells applications, with some recent efficiency results on n-type silicon solar cells and a review on various interdigitated backside contact structures, and key results of surface passivation for n-type silicon solar cells. It then presents an analysis of the influence of various parasitic effects on lifetime data, highlighting how these parasitic effects could affect the results of experiments that use lifetime data extensively. A plasma enhanced chemical vapour deposition process for depositing silicon nitride films is developed to passivate both diffused and non-diffused surfaces for n-type silicon solar cells application. Photoluminescence imaging, lifetime measurements, and optical microscopy are used to assess the quality of the silicon nitride films. An open circuit voltage of 719 mV is measured on an n-type, 1 Ω.cm, FZ, voltage test structure that has direct passivation by silicon nitride. Dark saturation current densities of 5 to 15 fA/cm2 are achieved on SiN-passivated boron emitters that have sheet resistances ranging from 60 to 240 Ω/□ after thermal annealing. Using the process developed, a more profound study on surface passivation by silicon nitride is conducted, where the relationship between the surface passivation quality and the film composition is investigated. It is demonstrated that the silicon-nitrogen bond density is an important parameter to achieve good surface pas-sivation and thermal stability. With the developed process and deeper understanding on the surface passivation of silicon nitride, attempts of integrating the process into the fab-rication of all-SiN passivated n-type IBC solar cells and laser doped n-type IBC solar cells are presented. Some of the limitations, inter-relationships, requirements, and challenges of novel integration of SiN into these solar cell devices are identified. Finally, a novel metallisation scheme that takes advantages of the different etching and electroless plating properties of different PECVD SiN films is described, and a preliminary evalua-tion is presented. This metallisation scheme increases the metal finger width without increasing the metal contact area with the underlying silicon, and also enables optimal distance between point contacts for point contact solar cells. It is concluded in this thesis that plasma enhanced chemical vapour deposited silicon nitride is well-suited for n-type silicon solar cells.
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Ning, Steven. "Simulation and process development for ion-implanted N-type silicon solar cells." Thesis, Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/47684.
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As the efficiency potential for the industrial P-type Al-BSF silicon solar cell reaches its limit, new solar cell technologies are required to continue the pursuit of higher efficiency solar power at lower cost. It has been demonstrated in literature that among possible alternative solar cell structures, cells featuring a local BSF (LBSF) have demonstrated some of the highest efficiencies seen to date. Implementation of this technology in industry, however, has been limited due to the cost involved in implementing the photolithography procedures required. Recent advances in solar cell doping techniques, however, have identified ion implantation as a possible means of performing the patterned doping required without the need for photolithography.
In addition, past studies have examined the potential for building solar cells on N-type silicon substrates, as opposed to P-type. Among other advantages, it is possible to create N-type solar cells which do not suffer from the efficiency degradation under light exposure that boron-doped P-type solar cells are subject to. Industry has not been able to capitalize on this potential for improved solar cell efficiency, in part because the fabrication of an N-type solar cell requires additional masking and doping steps compared to the P-type solar cell process. Again, however, recent advances in ion implantation for solar cells have demonstrated the possibility for bypassing these process limitations, fabricating high efficiency N-type cells without any masking steps.
It is clear that there is potential for ion implantation to revolutionize solar cell manufacturing, but it is uncertain what absolute efficiency gains may be achieved by moving to such a process. In addition to development of a solar specific ion implant process, a number of new thermal processes must be developed as well. With so many parameters to optimize, it is highly beneficial to have an advanced simulation model which can describe the ion implant, thermal processes, and cell performance accurately. Toward this goal, the current study develops a process and device simulation model in the Sentaurus TCAD framework, and calibrates this model to experimentally measured cells. The study focuses on three main tasks in this regard:
Task I - Implant and Anneal Model Development and Validation
This study examines the literature in solar and microelectronics research to identify features of ion implant and anneal processes which are pertinent to solar cell processing. It is found that the Monte Carlo ion implant models used in IC fabrication optimization are applicable to solar cell manufacture, with adjustments made to accommodate for the fact that solar cell wafers are often pyramidally textured instead of polished. For modeling the thermal anneal processes required after ion implant, it is found that the boron and phosphorus cases need to be treated separately, with their own diffusion models.
In particular, boron anneal simulation requires accurate treatment of boron-interstitial clusters (BICs), transient enhanced diffusion, and dose loss. Phosphorus anneal simulation requires treatment of vacancy and interstitial mediated diffusion, as well as dose loss and segregation. The required models are implemented in the Sentaurus AdvancedModels package, which is used in this study. The simulation is compared to both results presented in literature and physical measurements obtained on wafers implanted at the UCEP. It is found that good experimental agreement may be obtained for sheet resistance simulations of implanted wafers, as well as simulations of boron doping profile shape. The doping profiles of phosphorus as measured by the ECV method, however, contain inconsistencies with measured sheet resistance values which are not explained by the model.
Task II - Device Simulation Development and Calibration
This study also develops a 3D model for simulation of an N-type LBSF solar cell structure. The 3D structure is parametrized in terms of LBSF dot width and pitch, and an algorithm is used to generate an LBSF structure mesh with this parametrization. Doping profiles generated by simulations in Task I are integrated into the solar cell structure. Boundary conditions and free electrical parameters are calibrated using data from similar solar cells fabricated at the UCEP, as well as data from lifetime test wafers. This simulation uses electrical models recommended in literature for solar cell simulation.
It is demonstrated that the 3D solar cell model developed for this study accurately reproduces the performance of an implanted N-type full BSF solar cell, and all parameters fall within ranges expected from theoretical calculations. The model is then used to explore the parameter space for implanted N-type local BSF solar cells, and to determine conditions for optimal solar cell performance. It is found that adding an LBSF to the otherwise unchanged baseline N-type cell structure can produce almost 1% absolute efficiency gain. An optimum LBSF dot pitch of 450um at a dot size of 100um was identified through simulation. The model also reveals that an LBSF structure can reduce the fill factor of the solar cell, but this effect can be offset by a gain in Voc. Further efficiency improvements may be realized by implementing a doping-dependent SRV model and by optimizing the implant dose and thermal anneal.
Task III - Development of a Procedure for Ion Implanted N-type LBSF Cell Fabrication
Finally, this study explores a method for fabrication of ion-implanted N-type LBSF solar cells which makes use of photolithographically defined nitride masks to perform local phosphorus implantation. The process utilizes implant, anneal, and metallization steps previously developed at the UCEP, as well as new implant masking steps developed in the course of this study. Although an LBSF solar cell has not been completely fabricated, the remaining steps of the process are successfully tested on implanted N-type full BSF solar cells, with efficiencies reaching 20.0%.
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He, Yinghui. "Novel N-type Π-conjugated Polymers for all-polymer solar cells." Thesis, Bordeaux, 2017. http://www.theses.fr/2017BORD0651/document.
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Les cellules solaires organiques (OSC) apparaissent comme une technologie prometteuse pour les énergies renouvelables en raison de leur poids léger, leur grande flexibilité et leur processus de fabrication peu coûteux. Jusqu'à présent, la plupart des OPV ont utilisé des dérivés de Fullerene, tels que PCBM ou PC71BM, en tant qu'accepteur d'électrons dans la couche active, qui s'est avéré être un goulet d'étranglement pour cette technologie. Par conséquent, le développement d'accepteurs non-fullerene est devenu la nouvelle force motrice de ce domaine. Les cellules solaires tout-polymères (tous-PSC) qui ont les avantages de la robustesse, de la stabilité et de l'accessibilité ont déjà atteint PCE jusqu'à 9%. Ainsi, le développement de nouveaux matériaux accepteurs est impératif pour améliorer les performances de tous les PSCOrganic solar cells (OSCs) appear as a promising technology for renewable energy owing to their light weight, great flexibility and low-cost fabrication process. So far most of the OPV shave been using fullerene derivatives, such as PCBM or PC71BM, as the electron acceptor in the active layer, which have been proven to a bottleneck for this technology. Therefore,developing non-fullerene acceptors has become the new driving force for this field. All-polymer solar cells (all-PSCs) that have the advantages of robustness, stability and tunability have already achieved PCE up to 9%. Thus, developing novel acceptor materials is imperative for improving the performance of all-PSCs
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Edwards, Matthew Bruce ARC Centre of Excellence in Advanced Silicon Photovoltaics & Photonics Faculty of Engineering UNSW. "Screen and stencil print technologies for industrial N-type silicon solar cells." Publisher:University of New South Wales. ARC Centre of Excellence in Advanced Silicon Photovoltaics & Photonics, 2008. http://handle.unsw.edu.au/1959.4/41372.
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To ensure that photovoltaics contributes significantly to future world energy production, the cost per watt of producing solar cells needs to be drastically reduced. The use of n-type silicon wafers in conjunction with industrial print technology has the potential to lower the cost per watt of solar cells. The use of n-type silicon is expected to allow the use of cheaper Cz substrates, without a corresponding loss in device efficiency. Printed metallisation is well utilised by the PV industry due to its low cost, yet there are few examples of its application to n-type solar cells. This thesis explores the use of n-type Cz silicon with printed metallisation and diffusion from printed sources in creating industrially applicable solar cell structures. The thesis begins with an overview of existing n-type solar cell structures, previous printed thick film metallisation research and previous research into printed dopant sources. A study of printed thick-film metallisation for n-type solar cells is then presented, which details the fabrication of boron doped p-type emitters followed by a survey of thick film Ag, Al, and Ag/Al inks for making contact to a p-emitter layer. Drawbacks of the various inks include high contact resistance, low metal conductivity or both. A cofire regime for front and rear contacts is established and an optimal emitter selected. A study of printed dopant pastes is presented, with an objective to achieve selective, heavily doped regions under metal contacts without significantly compromising minority carrier lifetime in solar cells. It is found that heavily doped regions are achievable with both boron and phosphorus, but that only phosphorus paste was capable of post-processing lifetime compatible with good efficiencies. The effect of belt furnace processing on n-type silicon wafers is explored, with large losses in implied voltage observed due to contamination of Si wafers from transition metals present in the belt furnace. Due to exposure to chromium in the belt furnace, no significant advantage in using n-type wafers instead of p-type is observed during the belt furnace processing step. Finally, working solar cells with efficiencies up to 16.1% are fabricated utilising knowledge acquired in the earlier chapters. The solar cells are characterised using several new photoluminescence techniques, including photoluminescence with current extraction to measure the quality of metal contacts. The work in this thesis indicates that n-type printed silicon solar cell technology shows potential for good performance at low cost.
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Edler, Alexander [Verfasser]. "Development of bifacial n-type solar cells for industrial application / Alexander Edler." Konstanz : Bibliothek der Universität Konstanz, 2014. http://d-nb.info/1049892887/34.
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Zhang, Jie. "Roles of the n-type oxide layer in hybrid perovskite solar cells." Thesis, Paris 6, 2015. http://www.theses.fr/2015PA066634/document.
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Le soleil offre une ressource abondante et inépuisable d’énergie. Le photovoltaïque est la technologie la plus importante pour rendre l'énergie solaire utilisable car les cellules solaires photovoltaïques recueillent le rayonnement solaire et le convertissent en énergie électrique. Les cellules solaires à colorant (DSSC) ont été très étudiées en raison de leur faible coût, d’une technique de fabrication facile et une grande versatilité. Un dispositif classique DSSC comprend une photo-anode à colorant, une contre-électrode et un électrolyte contenant un couple redox et des additifs. Pour améliorer la stabilité de ces dispositifs, le remplacement de l'électrolyte liquide par des matériaux solides transporteur de trous a été étudié pour donner ce que l’on appelle des cellules solaires à colorant solides (ssDSSCs). Récemment, les pérovskites hybrides organique/inorganiques ont été introduites dans les systèmes ssDSSCs comme absorbeur de lumière. Les cellules correspondantes, appelées cellules solaires à pérovskite (PSC) ont ouvert une nouvelle ère en photovoltaïque en raison du faible coût de ce matériau et la grande efficacité de ces cellules. L'efficacité de conversion de puissance a augmenté de 3,8% en 2009 à un rendement certifié de 20,1% fin 2014. Les composants des cellules solaires à pérovskite comprennent: une couche compacte d'oxyde jouant le rôle de barrière pour les trous photogénérés, une couche de transport des électrons (un semiconducteur de type n), la couche de l’absorbeur de lumière à base de pérovskite d’halogénure de plomb, la couche de transport des trous et le contact arrière. Dans cette thèse, nous nous sommes concentrés sur la préparation et l’amélioration des propriétés de la couche de transport d'électrons et la couche de pérovskiteSolar energy is one of the most important resources in our modern life. Photovoltaic is the most important technology to render the solar energy usable since photovoltaic solar cells harvest light coming from sun and convert sunlight into electrical energy. Dye sensitized solar cells have gained widespread attention due to their low cost, easy fabrication technique and tunable choice for the device. A traditional DSSC device includes a dye-sensitized photo-anode, a counter electrode and an electrolyte containing a redox couple system and additives. To improve the device stability, the liquid electrolyte replacement by a solid state hole transport material has been studied in so-called solid-state dye sensitized solar cells (ssDSSCs). Recently, an amazing light perovskite absorber was introduced into the ssDSSC system to replace the dye, opening the new field of research. Perovskite solar cells (PSCs) open a new era in photovoltaic due to the low cost of this material and the high efficiency of these cells. The power conversion efficiency has risen from 3.8% to a certified 20.1% within a few years. The components in the perovskite solar cell include: the compact metal oxide blocking layer, the electron transport layer, the lead halide perovskite layer, the hole transport layer and the back contact. In this thesis, we focused on the preparation and improving the properties of the electron transport layer and the perovskite layer
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Ryu, Kyung Sun. "Development of low-cost and high-efficiency commercial size n-type silicon solar cells." Diss., Georgia Institute of Technology, 2015. http://hdl.handle.net/1853/53842.
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The objective of the research in this thesis was to develop high-efficiency n-type silicon solar cells at low-cost to reach grid parity. This was accomplished by reducing the electrical and optical losses in solar cells through understanding of fundamental physics and loss mechanisms, development of process technologies, cell design, and modeling. All these technology enhancements provided a 3.44% absolute increase in efficiency over the 17.4% efficient n-type PERT solar cell. Finally, 20.84% efficient n-type PERT (passivated emitter and rear totally diffused) solar cells were achieved on commercial grade 239cm2 n-type Cz silicon wafers with optimized front boron emitter without boron-rich layer and phosphorus back surface field, silicon dioxide/silicon nitride stack for surface passivation, optimized front grid pattern with screen printed 5 busbars and 100 gridlines, and improved rear contact with laser opening and physical vapor deposition aluminum. This thesis also suggested research directions to improve cell efficiency further and attain ≥21% efficient n-type solar cells which involves three additional technology developments including the use of floating busbars, selective emitters, and negatively charged aluminum oxide (Al2O3) film for boron emitter surface passivation.
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Frey, Alexander [Verfasser]. "Industrial n-Type Silicon Solar Cells with Co-Diffused Boron Emitters / Alexander Frey." Konstanz : Bibliothek der Universität Konstanz, 2018. http://d-nb.info/1161342966/34.
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Rothhardt, Philip [Verfasser], and Eicke [Akademischer Betreuer] Weber. "Co-diffusion for bifacial n-type solar cells = Co-Diffusion für bifaziale Solarzellen aus n-dotiertem Silizium." Freiburg : Universität, 2014. http://d-nb.info/1123481741/34.
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Benick, Jan [Verfasser]. "High-Efficiency n-Type Solar Cells with a Front Side Boron Emitter / Jan Benick." München : Verlag Dr. Hut, 2011. http://d-nb.info/1013526287/34.
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Heinz, Friedemann D., Matthias Breitwieser, Paul Gundel, Markus König, Matthias Hörteis, Wilhelm Warta, and Martin C. Schubert. "Microscopic origin of the aluminium assisted spiking effects in n-type silicon solar cells." Elsevier, 2014. https://publish.fid-move.qucosa.de/id/qucosa%3A72455.
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Contact formation with silver (Ag) thick film pastes on boron emitters of n-type crystalline silicon (Si) solar cells is a nontrivial technological task. Low contact resistances are up to present only achieved with the addition of aluminium (Al) to the paste. During contact formation, Al assisted spiking from the paste into the silicon emitter and bulk occurs, thus leading to a low contact resistance but also to a deterioration of other cell parameters. Both effects are coupled and can be adjusted by choosing proper Al contents of the paste and temperatures for contact formation. In this work the microscopic electric properties of single spikes are presented. These microscopic results, i.e. alterations of the local emitter doping density, the pronounced local recombination activity at the interface between spikes and Si and its influence on the charge collection efficiency, are used to explain the observed dependencies of global cell parameters on the Al content of contact pastes.
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Bock, Robert [Verfasser]. "Screen-printed aluminium-doped p+ emitters for the application to n-type silicon solar cells / Robert Bock." Hannover : Technische Informationsbibliothek und Universitätsbibliothek Hannover (TIB), 2011. http://d-nb.info/1017379106/34.
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Fournier, Olivier Jaques Henri. "Effects of the interfaces in planar hybrid lead trihalide perovskite solar cells with n-type and p-type inorganic charge transport layers." Thesis, KTH, Energiteknik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-246122.
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Perovskite-solceller är en framväxande och lovande tunnfilmsteknik, som uppnådde hög effektivitet på en ofantlig kort tid. Den nuvarande arkitekturen i cellen, som innefattar titanoxid och Spiro-OMeTAD (en organisk förening) som laddningstransportlager (CTL), saknar stabilitet och visar hysteretiskt beteende. För att bedöma dessa stora problem utvecklas oorganiska CTL i PV-samhället. I detta arbete utförs en grundlig översyn av litteraturen om dessa oorganiska CTL. Fyra av dem identifieras som bra kandidater på grund av de höga prestanda de uppnådde och deras kemiska stabilitet: SnO2, ZnO, CuSCN och NiO. Betydelsen av gränssnitten i denna typ av cell visas också. Numerisk simulering av CTLs utförs också med ett dedikerat 1D-modelleringsverktyg (SCAPS), vilket gör att vi kan föreslå viktiga parametrar för att optimera i en CTL. Slutligen studeras effekterna av gränssnittet på prestanda hos en perovskit-solcell med hyperspektral avbildning av cellens fotoluminescensrespons. Med hjälp av en korrekt passningsalgoritm ger denna icke-destruktiva metod insikt om de opto-elektroniska egenskaperna hos perovskiten som odlas på olika substrat.Perovskite solar cells are an emerging and promising thin film technology, which reached high efficiencies in an unprecedented short time. However, the current architecture of the cell, which includes titanium oxide and Spiro-OMeTAD (an organic compound) as charge transport layers (CTLs), lacks stability and shows hysteretic behavior. In order to assess these major issues, inorganic CTLs are developed in the PV community. This work performs a thorough review of the literature regarding these inorganic CTLs. Four of them are identified as good candidates because of the high performances they reached, and of their chemical stability: SnO2, ZnO, CuSCN and NiO. The significance of the interfaces in this kind of cell is also demonstrated. Numerical simulation of CTLs is also performed using a dedicated 1D modelisation tool (SCAPS), which allows us to propose key parameters to optimize in a CTL. Finally, the effects of the interface on the performances of a perovskite solar cell are studied with hyperspectral imaging of photoluminescence response of the cell. Using a proper fit algorithm, this non-destructive method gives insight into the opto-electronic properties of the perovskite grown on different substrates.
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Wehmeier, Nadine [Verfasser]. "Fabrication and analysis of co-diffused n-type silicon solar cells applying plasma-deposited diffusion sources / Nadine Wehmeier." Hannover : Technische Informationsbibliothek (TIB), 2017. http://d-nb.info/1136294945/34.
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Oliver, Cyril. "Dopage au Bore du Silicium Multicristallin de type N : application à la fabrication de cellules photovoltaïques par un procédé industriel." Thesis, Montpellier 2, 2011. http://www.theses.fr/2011MON20199/document.
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Cette thèse présente le développement d'un équipement permettant le dopage Bore des cellules photovoltaïques à base de silicium de type n. Un four de diffusion, appartenant à la société Semco Engineering a été développé pour tirer profit du procédé LYDOP (Leaktight Yield Doping en anglais), breveté par la société. Ce dernier a permis la mise au point d'un procédé de diffusion du Bore, régulé sous basse pression, intégrant une source dopante gazeuse à base de BCl3 afin d'effectuer le dopage de plusieurs plaques de silicium simultanément. Les principaux paramètres influençant le procédé de dopage ont été étudiés pour obtenir un dopage très uniforme sur plaque et sur nacelle. Une large gamme de résistances carrées d'émetteurs (de 40 à 100 ohm/sq) a été obtenue avec une uniformité inférieure à 5% sur plaque et sur nacelle. Le développement du procédé de dopage a conduit à étudier deux méthodes de fabrication d'une cellule photovoltaïque sur silicium multicristallin de type n. Plusieurs méthodes pour la formation de l'émetteur Bore sur une seule face ont été présentées : masquage (SiNx, SiO2), dopage back-to-back ou gravure chimique. De cette étude, deux procédés de fabrication (flowcharts) ont été développés pour la fabrication de cellules photovoltaïques : la première par gravure à l'hydroxyde de potassium (KOH) de l'émetteur, la seconde en effectuant le dopage bore des cellules en position back-to-back (dos à dos). Un rendement sur cellule de 13,2% et 14,4% a été obtenu respectivement pour chacune des flowcharts. Ces résultats, limités principalement par les étapes de passivation et de métallisation permettent de démontrer l'utilisation du procédé Bore comme solution à la formation des émetteurs p+This thesis presents the development of an equipment for boron doping of n-type multicrystalline silicon solar cells. A diffusion furnace was developed by Semco Engineering Company. It was built using LYDOP (LeakTight Yields DOPing) technology, patented by Semco. This one permits a simultaneous doping of a big amount of silicon wafers using regulated low pressure processes. Boron diffusion process development was carried out using LYDOP's specifications with BCl3 as gaseous doping source. Main parameters have been studied to control diffusion process. Several sheet resistance values of emitters were achieved (from 40 to 100 ohm/sq) with uniformity under 5% within wafer and within boat by tuning process parameters. Doping process development leads us to investigate how to create a single side emitter with n-type multicrystalline solar cells. Two fabrications flowcharts were presented: one using KOH emitter etches on backside and the other using back-to-back positioning during boron diffusion. Comparison between both flowcharts carried out to 13,2% and 14,4% efficiencies solar cells, respectively on each flowchart. Results are limited by passivation and metallization of emitters. However boron diffusion process demonstrate that LYDOP technology is well adapted to develop n-type solar cells
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Carter, Austin Roberts. "Magnetic field effects and self-assembled n-type nanostructures to increase charge collection in organic photovoltaics." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1324960593.
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Shu, Ying. "NOVEL SOLUTION PROCESSABLE ACCEPTORS FOR ORGANIC PHOTOVOLTAIC APPLICATIONS." UKnowledge, 2011. http://uknowledge.uky.edu/gradschool_diss/135.
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The field of organic electronics has become an increasingly important field of research in recent years. Organic based semiconductors have the potential for creating inexpensive, solution processed devices on flexible substrates. Some of the applications of organic semiconductors include organic field effect transistors, organic light emitting diodes and organic photovoltaics.
Functionalized pentacenes have been proven to be viable donor materials for use in organic photovoltaic devices. The goal of this research is to synthesize and test the viability of novel electron deficient pentacenes and pentacene based materials as acceptors to be used as drop-in replacements for PCBM in bulk-heterojunction organic solar cells.
Our goal was to tune and improve the efficiencies of these solar cells in a two pronged approach. First we tuned the open circuit voltage of these devices by determining the optimal energy levels of these acceptors by varying the number of electron withdrawing substituents on the acene core. We also tuned the short circuit current by chemically altering the solid state packing and optimizing device processing conditions. A preliminary structure-property relationship of these small molecule acceptors and photovoltaic device efficiency was established as a result.
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Shelton, Kerri. "NEW PHOTOVOLTAIC ACCEPTORS: SYNTHESIS AND CHARACTERIZATION OF FUNCTIONALIZED C-FUSED ANTHRADITHIOPHENE QUINONES." UKnowledge, 2011. http://uknowledge.uky.edu/gradschool_theses/92.
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Stable organic semiconductors are critical to produce inexpensive, efficient and flexible thin film organic solar cells. A current chemical focus is the synthesis of stable, electron-accepting materials to be utilized as an acceptor layer in photovoltaics.1 The Anthony group has shown that the functionalization of pentacene with suitable electron withdrawing groups provides a catalog of suitable acceptors for this purpose.2 These pentacenes can be further modified to pack in a unique 1-dimensional "sandwich herringbone" crystal packing, leading to improved device current.3 To improve the stability of acene acceptors, we have taken two hetero-atom themed approaches. First, we have studied the acenequinone as an electron-accepting chromophore.4 Further, we replaced the terminal aromatic rings with heterocycles, such as furan or thiophene. In order to enhance the crystal engineering versatility of the chromophore, we utilize c-fused heterocycles (rather than the more commonly used b-fused cycles seen in e.g. anthradithiophenes). The c-fused acenequinones can be tetra-functionalized with silylethynyl groups to influence crystal packing and increase solubility.5 The silylethyne groups are known to increase the photostability and lower the energy gap (Eg) of pentacenes.5 The functionalization of the silylethyne groups also aids in lowering the lowest unoccupied orbital (LUMO) of acene structures.5
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Hadouchi, Warda. "Etude de l'utilisation du ZnO comme contact de type n dans des dispositifs photovoltaïques à base de pérovskite hybride." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLX012/document.
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Les cellules solaires pérovskites hybrides ont marqué le monde du photovoltaïque avec une augmentation spectaculaire des rendements durant ces quatre dernières années. Avec des rendements dépassant 20% à l’heure actuelle, ce type de cellules suscite une attention particulière dans le monde scientifique. Dans l’architecture de la cellule solaire pérovskite, le TiO2 est l’oxyde le plus utilisé comme matériau collecteur d’électrons. Cette couche d’oxyde joue un rôle important dans la cellule, cependant le procédé d’élaboration du TiO2 requiert une étape de recuit à haute température. En plus des coûts élevés de production qu’elle implique, son utilisation exclut son application aux substrats sensibles aux hautes températures tels que les substrats plastiques flexibles par exemple.Cette thèse est centrée sur le remplacement du TiO2 par le ZnO en tant que couche collectrice d’électrons et bloqueuse de trous. Ce matériau représente une alternative intéressante en raison de ces propriétés comparables et même supérieures à celles du TiO2. L’intérêt du choix du ZnO réside dans sa simplicité de mise en œuvre. Ce matériau peut en effet être synthétisé à basse température (<100°C) et sous différentes structures. Dans cette étude nous avons fait le choix de considérer les croissances de ZnO par voie électrochimique et par pulvérisation cathodique. Dans des conditions de dépôts optimisées des couches de pérovskite et de ZnO, des rendements record de 14.2% et 9.7% ont été obtenus dans des architectures plane et nanostructurée respectivementPerovskite solar cells have marked the photovoltaic world with a spectacular increase of efficiencies over the last four years. With efficiencies exceeding 20%, this type of solar cells attracts a particular attention in the photovoltaic field. In the standard perovskite solar cell stack, TiO2 is used as an electron-collecting layer. This oxide layer plays an important role in the cell, however, its growth process requires a high temperature annealing step. In addition to the high production costs involved, its use also exclude its application to temperatures sensitive substrates such as flexible plastic materials.This thesis focuses on the replacement of the TiO2 bilayer by a ZnO electron-collecting and hole-blocking layer. We consider ZnO as an alternative to its comparable and even superior properties. One of the interests of the choice of ZnO lies in its simplicity of implementation and the possibility to synthesize it at low temperature (<100°C) and under different structures. The ZnO is here synthesized by electrochemical way and sputtering process. Under optimized deposition conditions of perovskite and ZnO layers, record efficiencies of 14.2% and 9.7% have been obtained in planar and nanostructured architecture respectively
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Senevirathna, Wasana. "Azadipyrromethene-based Metal Complexes as 3D Conjugated Electron Acceptors for Organic Solar Cells." Case Western Reserve University School of Graduate Studies / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=case1402062085.
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Hecht, [geb Wagener] Reinhard Johannes [Verfasser], Frank [Gutachter] Würthner, Klaus [Gutachter] Meerholz, and Matthias [Gutachter] Lehmann. "Processing and Characterization of Bulk Heterojunction Solar Cells Based on New Organic n-Type Semiconductors / Reinhard Johannes Hecht [geb. Wagener] ; Gutachter: Frank Würthner, Klaus Meerholz, Matthias Lehmann." Würzburg : Universität Würzburg, 2019. http://d-nb.info/1183576161/34.
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Favre, Wilfried. "Silicium de type n pour cellules à hétérojonctions : caractérisations et modélisations." Phd thesis, Université Paris Sud - Paris XI, 2011. http://tel.archives-ouvertes.fr/tel-00635222.
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Les cellules à hétérojonctions de silicium fabriquées par croissance de couches minces de silicium amorphe hydrogéné (a-Si :H) à basse température sur des substrats de silicium cristallin (c-Si) peuvent atteindre des rendements de conversion photovoltaïque élevés (η=23 % démontré). Les efforts de recherche ayant principalement été orientés vers le cristallin de type p jusqu'à présent en France, ce travail s'attache à l'étude du type n pour d'une part déterminer les performances auxquelles s'attendre avec cette nouvelle filière et d'autre part les améliorer. Pour cela, nous avons mis en œuvre des techniques de caractérisation des matériaux composant la structure et de l'interface (a-Si :H/c-Si) couplées à des outils de simulations numériques afin mieux comprendre les phénomènes de transport électronique. Nous nous sommes également intéressés aux cellules à hétérojonctions avec substrats de silicium multicristallin de type n, le silicium multicristallin étant le matériau le plus répandu actuellement dans la fabrication des cellules photovoltaïques.
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Letty, Elénore. "Identification and neutralization of lifetime-limiting defects in Czochralski silicon for high efficiency photovoltaic applications." Thesis, Lyon, 2017. http://www.theses.fr/2017LYSEI094/document.
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Les cellules photovoltaïques à base de silicium cristallin représentent plus de 90% du marché photovoltaïque mondial. Des architectures de cellules à haut rendement de conversion sont actuellement développées. Pour atteindre leurs performances maximales, ces architectures nécessitent néanmoins une amélioration des propriétés électriques des substrats de silicium cristallin. Les objectifs de cette thèse sont d’identifier les défauts limitant les propriétés électriques de ces substrats, de comprendre les mécanismes menant à leur formation et de proposer des moyens permettant leur neutralisation. Les matériaux étudiés sont des plaquettes de silicium Czochralski de type n, généralement utilisé pour les applications à haut rendement. Le four de tirage Czochralski a d’abord été modélisé afin de comprendre comment le passé thermique subi par le lingot de silicium lors de la cristallisation affecte la génération des défauts. Ces travaux ont été confirmés via des confrontations avec des données expérimentales, en utilisant une méthode originale développée dans le cadre de ce travail. Nous avons ensuite étudié l’influence du budget thermique lié aux procédés de fabrication des cellules sur la population de défauts. Nous avons ainsi pu montrer que la nature des défauts limitant les propriétés électriques du silicium était grandement modifiée selon le procédé de fabrication de cellules utilisé. Nous avons en outre mis en évidence une dégradation inattendue des propriétés électriques du silicium Czochralski de type n sous illumination, liée à la formation d’un défaut volumique inconnu. Les conditions de formation et de suppression de ce défaut ont été étudiées en profondeur. Enfin, les principaux défauts limitant les propriétés électriques du silicium ayant été identifiés et les mécanismes menant à leur formation compris, nous proposons dans un dernier chapitre des nouvelles techniques de caractérisation permettant de détecter les plaquettes défectueuses en début de ligne de production de cellules photovoltaïques, et ce à une cadence industriellePhotovoltaic solar cells based on crystalline silicon represent more than 90% of the worldwide photovoltaic market. High efficiency solar cell architectures are currently being developed. In order to allow their maximal performances to be reached, the electronic properties of their crystalline silicon substrate must however be enhanced. The goals of the present work are to identify the defects limiting the electronic properties of the substrate, to understand the mechanisms leading to their formation and to propose routes for their neutralization. The studied materials are n-type Czochralski silicon wafers, usually used as substrates for high efficiency photovoltaic applications. The Czochralski puller was first modeled in order to understand how the thermal history experienced by the silicon ingot during crystallization affects the defects generation. This study were validated through the comparison with experimental data using an original method developed in the frame of this work. We then studied the influence of the thermal budget associated to solar cell fabrication processes on the defects population. We thus showed that the nature of lifetime-limiting defects was completely changed depending on the solar cell fabrication process. Besides, we evidenced an unexpected degradation of the electronic properties of n-type Czochralski silicon under illumination, related to the formation of an unknown bulk defect. The formation and deactivation features of this defect were extensively studied. Finally, the main limiting defects being identified and the mechanisms resulting in their formation understood, we propose in a last chapter new characterization techniques for the detection of defective wafers at the beginning of production lines at an industrial throughput
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Faber, Carina. "Electrons, excitons et polarons dans les systèmes organiques : approches ab initio à N-corps de type GW et Bethe-Salpeter pour le photovoltaïque organique." Thesis, Grenoble, 2014. http://www.theses.fr/2014GRENY047/document.
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Cette thèse se propose d'explorer les mérites d'une famille d'approches de simulation quantique ab initio, les théories de perturbation à N-corps, pour l'exploration des propriétés électroniques et optiques de systèmes organiques. Nous avons étudié en particulier l'approximation dite de GW et l'équation de Bethe-Salpeter, très largement utilisées dès les années soixante pour les semiconducteurs de volume, mais dont l'utilisation pour les systèmes organiques moléculaires est très limitée. L'étude de quelques cas d'intérêt pour le photovoltaïque organique, et en particulier de petites molécules pour lesquelles sont disponibles des données expérimentales ou des résultats issus d'approches de chimie quantique, nous ont permis de valider ces approches issues de la physique du solide.Ce doctorat s'inscrit dans le cadre du développement d'un outil de simulation quantique spécifique (le projet FIESTA) dont l'objectif est de combiner les formalismes GW et Bethe-Salpeter avec les techniques de la chimie quantique, c'est-à-dire en particulier l'utilisation de bases localisées analytiques (bases gaussiennes) et des approches de type «résolution de l'identité» pour le traitement des intégrales Coulombiennes. Ce code est aujourd'hui massivement parallélisé, permettant, au delà des études de validation présentées dans ce travail de thèse, l'étude de systèmes complexes comprenant plusieurs centaines d'atomes. En cours de développement, l'incorporation d'approches hybrides combinant mécanique quantique et écrantage à longue portée par des approches modèles de milieu polarisable m'a permis d'une part de me familiariser avec le code et le développement méthodologique, et permet d'autre part d'envisager l'étude de systèmes réalistes en couplage avec leur environnement.Le manuscrit s‘ouvre sur une introduction au photovoltaïque organique afin de mettre en lumière les questionnements spécifiques qui requièrent le développement de nouveaux outils théoriques à la fois fiables en terme de précision et suffisamment efficaces pour traiter des systèmes de grande taille. Le premier chapitre est d'ordre méthodologique et rappelle les fondements des techniques ab initio de type champ-moyen (Hartree, Hartree-Fock et théorie de la fonctionnelle de la densité). En partant des principes de la photoémission, les théories de perturbation à N-corps et la notion de quasi-particule sont ensuite introduites, conduisant aux équations de Hedin et aux approximations GW et COHSEX. De même, à partir de la compréhension d'une expérience d'optique, le traitement des interactions électron-trou est présenté, menant à l'équation de Bethe-Salpeter. Le chapitre 2 introduit brièvement les spécificités techniques liées à l'implémentation des formalismes GW et Bethe-Salpeter. Les propriétés analytiques des bases gaussiennes et les principes mathématiques derrière les techniques de type «résolution de l'identité» et «déformation de contour», sont brièvement décrites. Le troisième chapitre présente les résultats scientifiques obtenus durant cette thèse. Le cas paradigmatique d'un polypeptide model nous permettra de discuter des spécificités de l'approche GW appliquée à des systèmes moléculaires afin d'obtenir des énergies de quasiparticule de bonne qualité. De même, l'utilisation de l'équation de Bethe-Salpeter pour l'obtention du spectre optique de ce système sera présentée, ainsi que le cas d'une famille de colorants d'importance pour les cellules de Graetzel (les coumarines). Finalement, nous explorons dans le cas du fullerène C60 et du graphène le calcul des termes de couplage électron-phonon dans le cadre de l'approche GW, c'est-à-dire au delà des approches standards de type théorie de la fonctionnelle de la densité. Notre étude vise à vérifier si une approximation statique et à écrantage constant au premier ordre permet de garder la qualité des résultats GW pour un coût numérique réduit. Après la conclusion, les appendices donnent le détail de certaines dérivationsThe present thesis aims at exploring the properties and merits of the ab initio Green's function many-body perturbation theory (MBPT) GW and Bethe-Salpeter formalisms, in order to provide a well-grounded and accurate description of the electronic and optical properties of condensed matter systems. While these approaches have been developed for extended inorganic semiconductors and extensively tested on this class of systems since the 60 s, the present work wants to assess their quality for gas phase organic molecules, where systematic studies still remain scarce. By means of small isolated study case molecules, we want to progress in the development of a theoretical framework, allowing an accurate description of complex organic systems of interest for organic photovoltaic devices. This represents the main motivation of this scientific project and we profit here from the wealth of experimental or high-level quantum chemistry reference data, which is available for these small, but paradigmatic study cases.This doctoral thesis came along with the development of a specific tool, the FIESTA package, which is a Gaussian basis implementation of the GW and Bethe-Salpeter formalisms applying resolution of the identity techniques with auxiliary bases and a contour deformation approach to dynamical correlations. Initially conceived as a serial GW code, with limited basis sets and functionalities, the code is now massively parallel and includes the Bethe-Salpeter formalism. The capacity to perform calculations on several hundreds of atoms to moderate costs clearly paves the way to enlarge our studies from simple model molecules to more realistic organic systems. An ongoing project related to the development of discrete polarizable models accounting for the molecular environment allowed me further to become more familiar with the actual implementation and code structure.The manuscript at hand is organized as follows. In an introductory chapter, we briefly present the basic mechanisms characterizing organic solar cells, accentuating the properties which seek for an accurate theoretical description in order to provide some insight into the factors determining solar cell efficiencies. The first chapter of the main part is methodological, including a discussion of the principle features and approximations behind standard mean-field techniques (Hartree, Hartree-Fock, density functional theory). Starting from a description of photoemission experiments, the MBPT and quasiparticle ideas are introduced, leading to the so-called Hedin's equations, the GW method and the COHSEX approach. In order to properly describe optical experiments, electron-hole interactions are included on top of the description of inter-electronic correlations. In this context, the Bethe-Salpeter formalism is introduced, along with an excursus on time-dependent density functional theory. Chapter 2 briefly presents the technical specifications of the GW and Bethe-Salpeter implementation in the FIESTA package. The properties of Gaussian basis sets, the ideas behind the resolution of the identity techniques and finally the contour deformation approach to dynamical correlations are discussed. The third chapter deals with the results obtained during this doctoral thesis. On the electronic structure level, a recent study on a paradigmatic dipeptide molecule will be presented. Further, also its optical properties will be explored, together with an in-depth discussion of charge-transfer excitations in a family of coumarin molecules. Finally, by means of the Buckminster fullerene C60 and the two-dimensional semi-metal graphene, we will analyze the reliability of two many-body formalisms, the so-called static COHSEX and constant-screening approximation, for an efficient calculation of electron-phonon interactions in organic systems at the MBPT level. After a short conclusion, the Appendix containing details and derivations of the formalisms presented before closes this work
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Fernando, Juwanmandadige Roshan. "Tuning the Opto-Electronic Properties of Core-Substituted Naphthalenediimides through Imide Substitution." Case Western Reserve University School of Graduate Studies / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=case1401984667.
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Lohmüller, Elmar [Verfasser]. "Transfer of the Metal Wrap Through Solar Cell Concept to n-Type Silicon / Elmar Lohmüller." Aachen : Shaker, 2016. http://d-nb.info/1081885750/34.
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Mojrová, Barbora. "Solární články z monokrystalického křemíku typu n s vysokou účinností." Doctoral thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2019. http://www.nusl.cz/ntk/nusl-408053.
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Tato dizertační práce je zaměřena vývoj a ověřování nových postupů přispívajících ke zvýšení účinnosti bifaciálních solárních článků založených na monokrystalickém křemíku n-typové vodivosti. Tato práce přináší nové poznatky o vylepšených výrobních procesech a postupech použitých během výroby článků v ISC Konstanz. V rámci práce byly vyrobeny solární články typu n-PERT (Passivated Emitter Rear Totally diffused) s vysokou účinností, a to pomocí standartních procesů a zařízení používaných běžně při průmyslové výrobě. Zapojení těchto průmyslových postupů a metod umožnilo ověřit možnosti výroby n-typových článků za použití téměř totožného vybavení, jaké je potřeba pro výrobu p-typových článků. Zvýšení účinnosti bylo založeno především na vylepšení jednotlivých procesních kroků. Experimenty popsané v této práci dosvědčují zlepšení procesu difúze bóru, přizpůsobení parametrů pasivační a antireflexní vrstvy nově navrženému emitoru, zlepšení procesu metalizace ve smyslu využití past neobsahujících hliník, testování tisku rozličných motivů spolu s různými sekvencemi výpalu. V rámci práce byla testována možnost zamezení jevu potenciální indukované degradace (Potential Induced Degradation – PID) pomocí vhodného složení ARC a pasivační vrstvy. Vyrobené n-typové solární články dosáhly maximální hodnoty účinnosti 20,9 %.
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Machado, Taila Cristiane Policarpi Alves. "Implementa??o de emissores p+com diferentes dopantes para c?lulas solares n+np+ finas." Pontif?cia Universidade Cat?lica do Rio Grande do Sul, 2018. http://tede2.pucrs.br/tede2/handle/tede/8010.
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Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES
The solar cells manufactured in n-type silicon, doped with phosphorus, do not present light induced degradation and they have the potential of achieving high efficiency due to the larger minority charge carrier lifetime. Besides, they are less susceptible to contamination by metal impurities. The aim of this work was to analyze different dopants to obtain the p+ region in n+np+ solar cells manufactured in Czochralski silicon wafers, solar grade, n-type, 120 ?m thick. The acceptor impurities used were B, Al, Ga, GaB and AlGa, deposited by spin-on and diffused at high temperature. The temperature, time and gases used in the process of diffusion were ranged. The sheet resistances (R?) of the diffused regions and the impurity concentration profiles were measured. We concluded that the B and GaB can be diffused at 970? C for 20 min to obtain p+ emitters with values of R? suitable to the production of solar cells with screenprinted metal grid. The Ga and AlGa require high temperatures (greater than 1100? C) and long times to produce doping profiles compatible with the production of solar cells. The Al did not produce low sheet resistance regions, even at temperatures of 1100? C. The use of argon gas instead of the nitrogen did not lead to the decreasing of the sheet resistance. The GaB is the only one doping material analyzed that can be a viable replacement for the B in the production of p+ emitter in n-type solar cells.The GaB was the only one doping material analyzed that allowed the manufacture of solar cells with the maximum efficiency of 13.5%, with the diffusion performed at 1020? C for 20 min. The FF was the main parameter that reduced the efficiency of solar cells doped with GaB when compared to the boron doped cells due to a lower shunt resistance. The n+np+ solar cell, 120 ?m thick, that achieved the highest efficiency was doped with boron and reached 14.9%, a value higher than the previously obtained in studies in the NT-Solar with thin silicon wafers.
As c?lulas solares fabricadas em l?minas de sil?cio tipo n, dopadas com f?sforo, n?o apresentam degrada??o por ilumina??o e t?m potencial de obten??o de maior efici?ncia devido ao maior valor do tempo de vida dos portadores de carga minorit?rios. Adicionalmente, s?o menos suscept?veis ? contamina??o por impurezas met?licas. O objetivo deste trabalho foi realizar uma an?lise de diferentes dopantes para obten??o da regi?o p+ em c?lulas solares n+np+fabricadas em l?minas de sil?cio Czochralski, grau solar, tipo n, com espessura de 120 ?m. Os elementos aceitadores utilizados foram o B, Al, Ga, GaB e AlGa, depositados por spin-on e difundidos em alta temperatura. Foram variadas as temperaturas, os tempos e os gases utilizados no processo de difus?o. Foi medida a resist?ncia de folha (R?) das regi?es difundidas e o perfil de concentra??o de impurezas em fun??o da profundidade. Foram desenvolvidas c?lulas solares com B, Ga, GaB e Al. Verificou-se que o B e GaB podem ser difundidos em temperatura de 970 ?C e por 20 min para obten??o de emissores com valores de R? compat?veis com a produ??o de c?lulas solares metalizadas por serigrafia. O Ga e AlGa necessitam de altas temperaturas (maiores que 1100 ?C) e tempos elevados para produzir perfis de dopantes compat?veis. O Al n?o produziu regi?es p+ de baixa R?, mesmo com a difus?o a 1100 ?C. O uso de Ar para substituir o N2 n?o acarretou em diminui??o da resist?ncia de folha. O GaB foi o ?nico dopante analisado que permitiu a fabrica??o de c?lulas solares com efici?ncia m?xima de 13,5 %, com difus?o a 1020 ?C por 20 min. O fator de forma foi o principal par?metro que reduziu a efici?ncia dos dispositivos com GaB quando comparado ao valor obtido com B devido a menor resist?ncia em paralelo. A c?lula solar n+np+ de 120 ?m de maior efici?ncia produzida neste trabalho foi dopada com boro e atingiu a efici?ncia de 14,9 %, sendo maior que as anteriormente obtidas em trabalhos realizados no NT-Solar com l?minas finas.
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Maake, Popoti Jacqueline. "Photovoltaic and gas sensing applications of transitional metal nanocomposites of poly(3-hexylthiophene)-titanium dioxide." University of Western Cape, 2021. http://hdl.handle.net/11394/8240.
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>Magister Scientiae - MScThis thesis starts with the reviewing of studies on the loading of noble metals and nanostructured metal oxides into bulk heterojunction organic solar cell device architectures. The reviews focused on the innovative developments in the use of various fullerene derivatives as electron acceptors in organic solar cells. It additionally reflected on the effect of metallic nanoparticles (NPs), such as gold (Au) and silver (Ag), on the performance of organic solar cells. Besides the metallic NPs, the effect of metal oxide nanoparticle loading, e.g. CuO, ZnO and TiO2, on the organic solar cell performance, and the use of noble metals doped TiO2 on the gas sensing application were reviewed.
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Tsai, Meng-Han, and 蔡孟翰. "Surface Passivation on N-type Silicon Solar Cells." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/41704707508113103834.
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碩士國立臺灣大學
電子工程學研究所
100
Wafer based solar cell accounts for the production of a large part in photovoltaic industry due to its stability and high efficiency. Although the technology of wafer based solar cell has been well-developed for conventional structure, there are still numerous new challenges existing for the high efficiency solar cell. In this thesis, the fabrication process of n-type crystalline silicon solar cell is demonstrated by using ion implantation to form the boron (p+) emitter and phosphorous (n+) back surface field. By means of appropriate annealing, the implanted dopants could be activated, and the damage caused by the implantation can be repaired. Moreover, surface passivation plays an important role in promoting the efficiency of cells due to its strong dependence of open circuit voltage (Voc). Therefore, the mechanism and characteristic of surface passivation were introduced in this work. Then, different passivation layers were designed and analyzed by quasi-steady-state photoconductance and photoluminescence (QSSPC) measurement. In this work, the SiNx/Al2O3 stack layers could provide the best passivation quality. And with the excellent passivation of SiNx/Al2O3 stack layers, efficiency more than 18% is shown in this work.
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Chiang, Chi-Yung, and 江奇詠. "Simulation of N-type Wafer-based Solar cells." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/92442947754614759886.
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碩士國立臺灣大學
電子工程學研究所
104
In this thesis, we focus on the simulation of n-type wafer-based solar cells. Through modeling and simulation, the performances of new photovoltaic devices can be predicted, and R&D costs can be reduced. Although two dimensional model simulation is well developed, it still fail to interpret some features of solar cells. Instead, three dimensional simulation can provide a more comprehensive structure, including the optical reflectivity, arrangement of electrodes and partial tunneling effect and so on. Therefore, we use technology computer aided design (TCAD) simulation software to carry out three dimensional model based simulation. In chapter 2, we focus on the simulation of passivated emitter rear locally diffused (PERL) and passivated emitter rear totally diffused (PERT) solar cells, including changes in cell structure, doping concentration, and electrode geometry. At the end of the chapter, we propose a new structure featuring honeycomb arrangement of electrodes. In chapter 3, we focus on the simulation of interdigitated back contact (IBC) solar cells. In addition to optimize the cell performance, we apply the honeycomb structure described in chapter 2 on the IBC cells along with the simulation of heterojunction with intrinsic thin layer IBC (HIT-IBC) solar cells. Finally, in chapter 4, we focus on the simulation of tunnel oxide passivated contact (TOPcon) solar cells, including the difference between n+ polysilicon and n+ amorphous silicon, the effect of tunnel oxide, and tunnel oxide uniformity issue. At the end of chapter 4, we propose a new solar cell structure, partial tunnel oxide passivated interdigitated back contact (Partial TOPIBC) solar cell, combined with the advantages of IBC solar cells and TOPcon solar cells.
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Huang, Yu-Hung, and 黃昱閎. "N-type silicon based homojunction and heterojunction solar cells." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/83478367825654828285.
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碩士國立臺灣大學
電子工程學研究所
99
Wafer based solar cell accounts for the production of a large part in photovoltaic industry due to its stability and high efficiency. Although the technology of wafer based solar cell has been well-developed for conventional structure, there are still numerous new challenges existing for high efficiency solar cell. In this thesis, the fabrication process of n-type silicon based homojunction solar cell is demonstrated by using ion implantation to form the boron (p+) emitter and phosphorous (n+) back surface field. By using appropriate annealing condition, The implanted dopants and damage introduced by implantation can be activated and repaired, respectively. Both rapid thermal annealing (RTA) and furnace annealing were investigated within this work. The efficiency is 14.5% by RTA process and 15.8% by furnace annealing process. Moreover, contact formation, contact material, and contact thickness conditions are taken into consideration for better efficiency. Therefore, experiments of various annealing conditions in forming gas after depositing contact, different material, and the thickness of contact are designed in this work. Next, surface passivation is very important for solar cell efficiency due to its strong dependence on open circuit voltage so it affects solar cell efficiency. Aluminum oxide (Al2O3) layers deposited by different method are compared for passivation ability by using quasi-steady-state photoconductance and photoluminescence (QSSPC) measurement. It means better passivation ability to passivate solar cell for higher effective carrier lifetime. In addition, QSSPC measurement also provide a way to estimating the implied open circuit voltage after forming the junction of solar cells. With the excellent passivation of Al2O3 deposited by atomic layer deposition (ALD), the efficiency more than 16% is shown in this work. Finally, the n-type silicon HIT solar cell with 11.1% efficiency is demonstrated to discuss the benefits from amorphous silicon emitter and suitable PDA condition.
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Liu, Jheng-Sin, and 劉政鑫. "Three-dimensional Simulation on N-type Wafer-based Solar Cells." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/78443460053757364724.
Full textAbstract:
碩士國立臺灣大學
光電工程學研究所
101
Modeling of photovoltaic devices has become more and more important and helpful not only to predict the performance of new devices but also to provide ideas and guidelines to industry without manufacture. The goal of this thesis is to provide an analysis of solar cells to the numerical simulation using state-of-the-art TCAD simulator featuring the capability to handle 2-D and 3-D geometries. The electrical and optical simulation of wafer based n-type Silicon solar cell is done by two-dimensional simulation. Firstly, the optical properties are analyzed by raytracing method. To calibrate the reflectance, some new optical models are introduced. Secondly, we simulate the electrical properties of solar cells. Other than Jsc, Voc, fill factor (FF) and efficiency, we also look into external quantum efficiency (EQE) and reflectance of the simulated cell with reference to fabricated cell. Finally, the angular effects on optical and electrical simulations are reported. We look into the optical and electrical issue by 3D simulations. In optical part, non-uniformity and random position issue of solar cells are discussed. The random position fills the skyline of textures. This enhances the light trapping ability of the solar cell and decreases the reflectance. However, non-uniformity of textures makes space between textures. It let light escape from texture surface leading higher reflectance. The electrical properties are discussed. The series resistance from metal grid is simulated. The simulation optimizes the thickness of metal grid and resistivity of different material. The width of busbar for planar solar cells is simulated. The different materials of metal grids, contact resistance, and height of metal grids are investigated to optimize the structure of the grid on the top of cells. The 3D simulation is used to optimize the size and shape of the finger on the top of the cells. The tradeoff between short circuit Jsc to favor small grid area and the FF to favor large grid area leads to an optimum value of finger width about ~20 μm, with silver (14.7nΩ-m), contact resistance (1mΩ-cm2), and height of metal grids (30-40 μm). To reduce the I2R drop of the finger, triangle and multi-segments are considered. Given the same metal area, the short circuit current and the open circuit voltage of the different finger design are similar. The resistive loss of triangle and multi-segment fingers are smaller than rectangular (conventional) fingers. The FFs of multi-segment, and triangular fingers are larger than the those of rectangular fingers for the same shadow area. The multi-segment fingers have comparable FF with triangular fingers.
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Wei-ChihCheng and 鄭韋志. "Polymer solar cells with indene-C60 bisadduct as n-type semiconductor." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/96497421086156315194.
Full text
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Lai, Shih-wei, and 賴世偉. "Fabrication of Solar Cells using Cuprous Oxide on N-type Bulk Silicon." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/34486656442928217725.
Full textAbstract:
碩士國立中山大學
光電工程學系研究所
104
In this study, we fabricate heteorjunction solar cells which are composed of P-type cuprous oxide on N-type silicon wafer. First, the silicon wafer was textured with KOH alkaline solution to lower the weighted reflection. In the following, we used thermal oxidation to grow silicon oxide on the surface of silicon wafer, and removed the grown oxide with wet etching. There are two reasons to do so. One is to lower the sharpness of pyramid structure, and another is to remove particles which could attach to the silicon surface during fabricating process. Moreover, we do the surface passivation of silicon using supercritical fluid to repair defects. Finally, we deposited P-type cuprous oxide on silicon substrate with both solution process and reactive sputtering and completed the devices by fabricating the metal electrodes. The reflectivity of silicon substrate was reduced from 29.6% to 15.3% by texturizing the Si surface. The SEM pictures also showed that the sharpness of pyramid structure was successfully reduced with thermal oxidation and etching. However, this led to an increase of reflectivity. The reflectivity increased from 15.3% to 17.7% after removing 0.5μm thermal oxide on the Si surface. Finally, the performance of devices was measured by solar simulator at AM1.5. The best devices showed an open circuit voltage (VOC ) of 0.3V、a short circuit current density (JSC) of 1.03mA/cm2、a full factor (FF) of 0.37 and an energy conversion efficiency (η) of 0.11%. The carrier lifetime of the textured silicon wafer which is passivated with supercritical fluid is only 94.1μs. The carrier lifetime must be improved before a high performance Cu2O/n-Si heterojunction solar call can be obtained.
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Chen, Hsiang-An, and 陳祥安. "Synthesis of novel Solar Cells using n-type ZnO Nanowire and p-type CuO thin films." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/4xaz89.
Full textAbstract:
碩士國立高雄海洋科技大學
微電子工程研究所
101
In this study, pn heterojunction were preparation by integration of p-type Copper Oxide (CuO) film on n-type Zinc Oxide (ZnO) nanowires. Where the ZnO nanowires were grown through hydrothermal method and CuO by sputtering and sol-gel deposition. The samples and devices were analyzed using scanning electron microscopy, X-ray Diffraction (XRD), Hall Effect measurement UV-VIS spectroscopy and electrical characteriz -ation. This thesis is divided into three parts. First, ZnO nanowires were grown onto p-type forming a pn-Cell that reduces light reflectivity from 41.4% to 21.73% and enhanced photovo- ltaic performance. Second, CuO thin films were prepared by sol-gel method. It was found that samples sintered at temperature of 300℃ possesses the struc -tural and electrical properties. Low-cost solar cells were constructed using n-type silicon/ ZnO nanowires /p-type CuO and evaluated using a solar simulator Finally, CuO thin films were prepared by sputtering and integrated into heterojunction and electrically tested for solar cell performances. Keywords: Copper Oxide、Aqueous Solution Method、Solar Cells、Sol-Gel Method、Magnetron Sputtering
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Lin, Kuan-Bo, and 林冠伯. "Co-diffusion by spin-on dopants for bifacial n-type silicon solar cells." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/24qx9d.
Full textAbstract:
碩士國立中央大學
材料科學與工程研究所
103
In conventional bifacial n-Si solar cells fabrication processing, raw Si wafers have to be annealed in high temperature furnace at least two times to form emitter and back surface field (BSF). However, these processing have many disadvantages and waste time in the industrial. In this thesis, we used the co-diffusion by spin-on dopants processing to form the p+ emitter and n+ BSF in the ONE step for n-type Si which could reduce the annealing time and manufacturing cost in the industrial. The two structures were fabricated to diffuse in high temperature and characterized in SIMS profiles, effective lifetime, inverse saturation current density and surface recombination velocity (SRV). Finally, the structure in highly performance for surface passivation were fabricated in bifacial n-Si solar cells in order to improve and modify the conventional manufacturing method. As our result showed, co-diffusion structure for barrier layer on phosphorous side had better surface passivation properties. This structure would be demonstrated in the bifacial n-Si solar cells for efficiency = 11.4 %, Voc = 591.6 mV, Jsc = 33.6 mA/cm2 and fill factor = 62 %.
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Lien, Hsu Sheng, and 連旭昇. "Fabrication of N-Type Solar Cells by Boron Ion Implant and Phosphorus Diffusion." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/76699146793072018256.
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Li, Chien, and 李謙. "The study of hybrid solar cells based on N-type Si substrate with PEDOT:PSS." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/su4ss9.
Full textAbstract:
碩士國立清華大學
材料科學工程學系
105
Silicon is a high-performance material for solar cells. The hybrid solar cells combine the advantages of organic solar cells and inorganic solar cells. This study used PEDOT:PSS as the p-type organic semiconductor material and Si substrate as the n-type inorganic material to fabricate hybrid solar cells. Various device fabrication parameters were investigated systematically. We first discussed the influences of the native oxide forming time on the PEDOT:PSS coating. Then, we studied the influences of PEDOT:PSS coating spin rate and coating time on the device performance. The optimal device fabrication parameters were found to be a native oxide forming time of 4 hr and the PEDOT:PSS coating spin rate and time of 3000 rpm and 60 s, respectively. The Si/PEDOT:PSS solar cell based on the optimal fabrication parameters has exhibited a power conversion efficiency of 5.811%.
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Hung, Wei-Jie, and 洪偉傑. "Fabrication of Transparent Conductive Oxides for Single-Crystalline n-type Silicon Hetero-Junction Solar Cells." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/50732695248536570600.
Full textAbstract:
碩士華梵大學
機電工程學系博碩專班
98
This paper is aimed to improve the efficiencies of silicon solar cell using semiconductor fabrication technologies. The research first adopts n-type (100) silicon wafers as substrates, and applies KOH etching in the photolithography process to form inverted pyramid structures. The density of the inverse pyramid structures is varied to investigate its impact factor on the reflectivity for the solar cells. In addition, the paper performs high-density plasma chemical vapor deposition to fabricate amorphous silicon thin films. Then, the author can study solar cells performances with single crystal / hydrogenised amorphous silicon heterojunctions, the effects of p-type amorphous silicon films deposited over p-type single crystal films, as well as the influences from p-type amorphous silicon layers and intrinsic layers. Also, the research executes ion implantation to fabricate BSF layers, which are intended to decrease the carrier recombination rate within the interfacing regions, and to improve the minority carrier collection rates. Furthermore, this research employes RF sputtering system to fabricate AZO transparent conductive thin films, and then learns the effects of adjusted processing parameters to the electrical and optical film properties. In the end, hydrogen plasma is used to perform the film post-processing, and the conductive films are then utilized as solar cell electrodes. After using a semiconductor parameter analyzer to perform a series of experimental measurements, the obtained IV curves suggest that the prototyped solar cells can obtain an open circuit voltage Voc = 0.60V, a short circuit current Jsc = 30mA/cm2, a fill factor FF of 62.08%, and an actual efficiency is about 11.13%.
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Hecht, [geb Wagener] Reinhard Johannes. "Processing and Characterization of Bulk Heterojunction Solar Cells Based on New Organic n-Type Semiconductors." Doctoral thesis, 2019. https://nbn-resolving.org/urn:nbn:de:bvb:20-opus-161385.
Full textAbstract:
This thesis established the fabrication of organic solar cells of DA dye donors and fullerene acceptors under ambient conditions in our laboratory, however, with reduced power conversion efficiencies compared to inert conditions. It was shown that moisture had the strongest impact on the stability and reproducibility of the solar cells. Therefore, utilization of robust materials, inverted device architectures and fast fabrication/characterization are recommended if processing takes place in air. Furthermore, the dyad concept was successfully explored in merocyanine dye-fullerene dyads and power conversion efficiencies of up to 1.14 % and 1.59 % were measured under ambient and inert conditions, respectively. It was determined that the major drawback in comparison to comparable BHJ devices was the inability of the dyad molecules to undergo phase separation. Finally, two series of small molecules were designed in order to obtain electron transport materials, using the acceptor-core-acceptor motive. By variation of the acceptor units especially the LUMO levels could be lowered effectively. Investigation of the compounds in organic thin film transistors helped to identify promising molecules with electron transport properties. Electron transport mobilities of up to 7.3 × 10−2 cm2 V−1 s−1 (ADA2b) and 1.39 × 10−2 cm2 V−1 s−1 (AπA1b) were measured in air for the ADA and AπA dyes, respectively. Investigation of selected molecules in organic solar cells proved that these molecules work as active layer components, even though power conversion efficiencies cannot compete with fullerene based devices yet. Thus, this thesis shows new possibilities that might help to develop and design small molecules as substitutes for fullerene acceptorsIn dieser Arbeit wurde gezeigt, dass die Herstellung und Charakterisierung von organischen Solarzellen auf Basis von kleinen DA-Farbstoffen in Kombination mit Fullerenakzeptoren unter Umgebungsbedingungen möglich ist. Außerdem konnte herausgefunden werden, dass die Luftfeuchtigkeit den größten Einfluss auf die Stabilität und die Reproduzierbarkeit der organischen Solarzellen hat. Aus diesem Grund sind der Austausch labiler Komponenten, die Verwendung von invertierten Bauteilarchitekturen sowie eine zügige Herstellung und Charakterisierung bei Prozessierung an Luft zu empfehlen. In weiteren Experimenten konnte das Dyadenkonzept erfolgreich angewendet werden, sodass sich Effizienzen von 1.14 und 1.59 % unter ambienten bzw. inerten Bedingungen messen ließen. Das Unvermögen der Dyaden, separate Phasen aus Donor- und Akzeptorverbindung zu bilden, konnte als größte Schwäche der Verbindungen ausgemacht werden. Schlussendlich wurden zwei Serien von Molekülen mit der Absicht Elektronentransportmaterialien zu generieren basierend auf einem Akzeptor-Kern-Akzeptor-Strukturmotiv entworfen. Die Variation der Akzeptoren ermöglichte in der Tat eine systematische Absenkung der Grenzorbitale und insbesondere der LUMO-Niveaus. Weiterhin wurden die Verbindungen in organischen Dünnfilmtransistoren untersucht, um mehr über ihre Ladungstransporteigenschaften zu erfahren. Dabei konnten Moleküle ausgemacht werden, die zum Elektronentransport an Luft in der Lage sind. Für die besten ADA- und AπA-Farbstoffe konnten so jeweils Elektronenmobilitäten von 7.3 × 10−2 cm2 V–1 s–1 (ADA2b) und 1.39 × 10−2 cm2 V–1 s–1 (AπA1b) gemessen werden. Weitere Untersuchungen von ausgewählten Verbindungen in organischen Solarzellen, konnten beweisen, dass diese neu kreierten Moleküle im Prinzip als Aktivmaterialien funktionieren können, wenn auch die erzielten Effizienzen noch nicht mit denen von Fulleren-basierten Solarzellen konkurrieren konnten. Damit zeigt diese Arbeit neue Möglichkeiten auf, die bei der Entwicklung und dem Design von kleinen Molekülen als Alternativen zu Fullereneakzeptoren hilfreich sein können
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Siram, Raja Bhaskar Kanth. "Investigation Of Phase Separation In Bulk Heterojunction Solar Cells Via Self-assembly Approach And Role Of Organic Fluorine In Design Of n-type Molecular Semiconductors." Thesis, 2012. http://hdl.handle.net/2005/2306.
Full textAbstract:
The present thesis is focused on rational design and synthesis of π-conjugated donoracceptor-donor (D-A-D) type oligomers and D-A type copolymers. Thesis is organized in seven chapters, apart from introduction remaining six chapters are grouped into two parts (A and B). Part A deals with Chapters 2, 3, 4 and Part B contains chapters 5, 6 and 7. A brief discussion on the content of individual chapters is provided below.
Chapter 1 discusses the introduction to organic solar cell with operating principles and effect of spinodal decomposition on stability of the devices is presented. The status and literature related to the improvement of life time of the organic solar cells by self-assembly approach has been explored. In addition, design and synthesis of the fluorine substituted π-conjugated organic semiconductors for n-type OFETs and OLED has been discussed.
Part A
This part of the thesis attempt to address some of the challenges listed below
(1) Investigation of miscibility of binary components in bulk heterojunction solar
cells through H-bonding approach.
(2) Synthesis of new low band gap molecular semiconductors having H-bonding
sites.
(3) Fabrication of bulk heterojunction solar cell devices using these new molecules
and exploring the photovoltaics performance.
Chapter 2, donor-acceptor-donor (D-A-D) concept has been employed to design low band gap oligomers named as TTB. Barbiturate functional group has been utilized to explore the concepts of supramolecular chemistry. It is shown that, TTB molecule self-organizes via intermolecular H-bonding between barbituric acid units. Interactions between the oligothiophene subunits were also found to be important, affording nanoribbons that were observed by atomic force and transmission electron microscopy. The applicability of TTB for organic electronic applications was investigated by fabricating organic field-effect transistors (OFETs) and organic photovoltaic device. The crystalline nanoribbons were beneficial in understanding the phase morphology of PCBM and TTB blend.
Chapter 3, the self-assemble property of TTB was disrupted by the substitution of methyl group on the nitrogen of the barbituric acid moiety. The optical and electrochemical properties of the new derivative have been investigated by UV-Visible spectroscopy, photoluminescence spectroscopy and cyclic voltammetry. Further investigations on the effect of self-assembly on organic solar cells were carried out by fabricating BHJ and OFET. The results proved that the self-assembly within the donor moieties led to complete phase separation between the donor and acceptor which had an adverse effect on the photovoltaic performance.
Chapter 4, the conjugation of TTB was extended by the synthesis of two new copolymers by polymerizing with two oliogothiophene (terthiophene and benzobithiophene) derivatives with different donating strength. The investigation of photophysical and electrochemical properties of copolymers were studied by varying the donating strength. As we increase the donating strength of oligothiophenes, the intramolecular charge transfer band of DA copolymers was red shifted. Further, density functional theory (DFT) calculation of these materials was carried out to get insight into their photophysical properties.
Part B
This part of the thesis attempt to address some of the challenges listed below
(1) Investigation of fluorine substituted organic semiconductos like 2,2’ bithiazole
and pheanthroimidazole.
(2) Synthesis of pentafluoro phenyl appended derivatives of 2,2’ bithiazole and
pheanthroimidazole.
(3) Fabrication of OFETs and OLEDs using these new molecules and elucidated
the device performance with molecular structure.
Chapter 5, pentafluorophenyl appended 2,2’-bithiazole derivatives were synthesized. The single crystal x-ray diffraction studies shows the unusual strong type-II F•••F interactions within the distance of 2.668 Å, at an angle of 89.14° and 174.15°. It also shows the usual type-I F•••F interaction within the distance of 2.825Å, at an angle of 137.38° and 135.93°. Upon bromination type-II Br•••Br interaction was observed and the packing was further stabilized by S•••Br interactions. The conjugation was further extended with different aromatic and heteroaromatic substituents and synthesized the star shaped structure. The band gap as well as the electronic energy levels was tuned by substituting various aromatic and heteroaromatic substituents. These star shaped derivatives shows electron mobilities in the order of 10-4 to 10-3cm2/Vs.
Chapter 6, Novel D-A copolymers were synthesized by Stille condensation of electron acceptor fluorinated phenanthroimidazole with electron donors like terthiophene and benzobithiophene. Prior to that insoluble pentafluoro phenyl phenanthroimidazole was Nalkylated in presence of DMF which concurrently resulted in C-F activation of the pentafluoro phenyl moiety. As we increase the donor strength from benzobithiophene to terthiophene the absorbance spectra was red shifted from 446 nm to 482 nm in solution and 455 nm to 484 nm in solid state. The band gap of these copolymers was found to be 2.4 eV for PIBDT and 2.2 eV for PIDHTT from the absorbance spectra. The photoluminescence data shows that these materials are promising for the yellow colour as well as orange colour displays, of narrow wavelength range (FWHM 40 nm for PIBDT and 35 nm for PIDHTT), which can be achieved just by the manipulation of donor moieties in the copolymers. The preliminary electroluminiscence data shows high brightness of 888cd/m2
(orange luminescence) for PIDHTT and 410cd/m2 (yellow luminescence) for PIBDT.
Chapter 7, Acenaphtho[1,2-b]quinoxaline based donor–acceptor type low band gap
conjugated copolymers were synthesized by Stille coupling reaction with the
corresponding oligothiophene derivatives. The optical properties of the copolymers were characterized by ultraviolet-visible spectrometry while the electrochemical properties were determined by cyclic voltammetry. The band gap of these polymers was found to be in the range of 1.8-2.0 eV as calculated from the optical absorption band edge. The intense charge transfer band in absorption spectra shows the significant effect of acceptor in the copolymers. X-ray diffraction measurements show weak π–π stacking interactions between the polymer chains. The OFET devices fabricated using these co-polymers showed dominant p-channel transistor behavior with the highest mobility of 1×10-3cm2/Vs.
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Wu, Jia-en, and 吳嘉恩. "The Influence of Different N-Type Layer Materials on the Photovoltaic Properties of Organic Solar Cells." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/55917373075552489787.
Full textAbstract:
碩士國立中正大學
光機電整合工程所
95
Organic solar cells based on p-n heterojunction with different n-type layer materials have been fabricated by high vacuum evaporator system. In our study, the device configurations of organic solar cells using multilayer structure were ITO/various n-type layer/ZnPc (550 Å)/Ag (1000 Å). Two different n-type layer materials were used: 3,4,9,10-perylene-tetracarboxylic dianhydride (PTCDA) and fullerene (C60). In this configuration, ITO, ZnPc, and Ag were used as cathode, p-type layer, and anode respectively. The effects of different n-type layer materials on the photovoltaic properties of organic solar cells have been systematically investigated. Evidence showed that the device with PTCDA n-type layer exhibits better optical absorption ability, leading to obtain more effective absorption of photons. PTCDA also possesses a shallow bulk trap level, providing more detrapping electrons from the bulk trap states into the lowest unoccupied molecular orbital states for transporting in PTCDA. We suggest that these are the main contributing factors to the superior photovoltaic performances of this device.
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Hsu, Chen-Kang, and 許朕綱. "Fabrication of spin-on dopants co-diffusion process and applying to bifacial n-type silicon solar cells." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/uta3au.
Full textAbstract:
碩士國立中央大學
材料科學與工程研究所
104
In conventional n-type silicon solar cells fabrication processing, the emitter and the back surface field (BSF) are formed through two-step diffusion. However, there are some disadvantages in traditional two-steps diffusion process such as complicated procedures, high thermal budge, toxic and cost. In conventional diffusion process, BBr 3 and POCl 3 are usually used to be the dopants sources. In this thesis, it was used phosphorous acid and boron acid to be the dopants sources. We also combined the co-diffusion process and spin-on dopants process to form the emitter and BSF of n-type silicon solar cells. It could effectively reduce the annealing time and decrease the production cost. Besides, the dopants sources (phosphorous acid and boron acid) are non-toxic. This novel process is compared to the traditional two-step diffusion by spin-on dopants. The lifetime measurement and implied open-circuit voltage measurement are carried out. The efficiency of the bifacial n-type silicon solar cell=11.5%, Voc =597.2 mV, Jsc =33.0 mA/cm2 and fill factor =58.5 %.
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Silva, Rodrigo Amaro e. "Empirical optimization and implementation of boron emitter on n-type silicon solar cells using BBR3 liquid source." Master's thesis, 2014. http://hdl.handle.net/10451/15931.
Full textAbstract:
Tese de mestrado integrado em Engenharia da Energia e do Ambiente , apresentada à Universidade de Lisboa, através da Faculdade de Ciências, 2014O presente trabalho aborda o estudo e optimização de um processo de difusão com fonte líquida de BBr3 para a formação de uma camada p+ em substrato de silício de tipo-n, sendo este passo uma das maiores limitações actuais para a implementação de células solares de alta eficiência de custo acessível baseadas neste material e com emissor de boro. Uma revisão do estado da arte e apresentada, com os seguintes tópicos: propriedades do silício de tipo-n e seu contexto histórico; metalização e passivação de camadas p+; propriedades de um emissor de boro e difusão de boro baseada numa fonte líquida de BBr3. De seguida, um estudo experimental de diversos parâmetros do processo de difusão e o seu impacto no emissor obtido, sendo os parâmetros: temperatura do borbulhador de BBr3 (e desejável estabilidade); fluxo de N2; fluxo de N2-BBr3; espaçamento entre bolachas na estrutura de suporte e a duração da etapa de pré-depósito. Para cada experiência procurou-se verificar a presença de uma capa rica em boro (BRL) e avaliar a homogeneidade da difusão através de uma avaliação visual do óxido formado e medidas de resistividade de capa. Posteriormente, um processo de difusão em que apenas era dopada uma bolacha foi testado para dopar diversas bolachas num só processo, tendo depois exigido uma optimização dos parâmetros de difusão. A remoção da BRL foi testada através de uma oxidação química e de uma oxidação térmica. Concluindo, verificou-se que um bom controlo da temperatura do borbulhador e um requisito e que esta deveria estar a pelo menos 20ºC de forma a se obter uma dopagem eficaz. Todos os outros parâmetros mostraram ter impacto no emissor obtido e no óxido formado apesar de não se ter obtido nenhuma dopagem nem oxido que fossem homogéneos. Obter um óxido homogéneo e um requisito crucial já que pode indicar tanto uma dopagem como a formação de uma BRL também homogéneas, permitindo uma remoção eficaz da camada que induz recombinação tendo sido verificado que para os óxidos heterogéneos obtidos, tanto a oxidação química como térmica apenas resultaram numa remoção parcial da BRL. Verificou-se ainda que um processo de difusão estudado para uma única bolacha não e imediatamente conversível para dopar várias bolachas num só processo já que uma dopagem ineficaz foi obtida e portanto requerendo uma optimização de parâmetros adicional. Finalmente, são ainda sugeridas linhas de trabalho futuro de forma a dar sequencia ao presente trabalho.
The present work focus on the study and optimization of a BBr3 diffusion process for a p+ layer formation on n-type Si wafers, as it is currently one of the main limitations for the implementation of cheap high-efficiency solar cells based on this material with a boron emitter. A state of the art review is presented, covering the following topics: n-type silicon properties and its historical context; p+ layer metallization and passivation; boron emitter properties and boron diffusion based on a BBr3 liquid source. Next, an experimental study of several diffusion process parameters and their impact on the resulting emitter is presented, being the parameters: BBr3 bubbler temperature (and desirable stability); N2 flow; N2-BBr3 flow; wafer spacing in the boat structure and predeposition step duration. For each experiment it was verified the presence of a BRL while evaluating the diffusion homogeneity through a visual evaluation of the formed oxide and sheet resistance measurements. Afterwards, a selected single-wafer process was tested for batch process conversion, which then required a parameters optimization. The removal of the BRL through both chemical and thermal oxidation was also tested. In conclusion, it was verified that a good control of the bubbler temperature is required and that it should be at least at 20 ºC in order to obtain an effective doping. All other parameters showed to have an impact in the formed emitter and resulting oxide, although no homogeneous doping nor oxide thickness were achieved. The formation of a homogeneous oxide is a crucial requirement as it can indicate a good homogeneity in both the doping and BRL formation, impeding an effective removal of this recombination-inducing layer. This was verified as both oxidation techniques tested resulted in only a partial removal of the BRL. It was also verified that a single-wafer process is not immediately convertible into a batch process as an ineffective doping was obtained, therefore requiring further parameter optimization. Finally, future work lines are suggested in order to go on with the present work.
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Chuang, Tien-Shao, and 莊天劭. "Process Simulation of N-type Si wafer, and Analysis of Interdigital Back Contact(IBC) and Bifacial Solar Cells." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/60668940257883573159.
Full textAbstract:
碩士國立臺灣大學
光電工程學研究所
100
Wafer based silicon solar accounts for a large part in photovoltaic industry is because of the stability of silicon and the mature development in semiconductor industry. In the thesis, the simulation results are based on the N-type silicon based solar cell. According to the solar cells like interdigital back contact (IBC) solar cells by SunPower company and bifacial solar cells by Yingli solar, which both have been in mass production, the simulation and analysis are performed, respectively. Dopants are implanted by ion plantation. We analyze effects of O2 on the sheet resistance of boron doped region when it is performed thermal oxidation. Later, considering the real activation conditions, we construct a simulation model calibrated with the experimental data to predict the sheet resistance under different activation conditions. Doping profiles calibrated above can be use to simulate the efficiency of N-type solar cell. We discuss the advantages and design rules for bifacial solar cells. Finally, by reverse engineering, we obtain the design parameters for the IBC solar cell, and the efficiency of that parameters are simulated by Sentaurus of Synopsys company.
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Chang, Bin-hsuan, and 張濱璿. "The Influence of Different P-Type Layer Materials on the Photovoltaic Characteristic of Organic p-i-n Heterojunction Solar Cells." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/18161166363062431815.
Full textAbstract:
碩士國立中正大學
光機電整合工程所
95
The influence of the p-type layer on the performance of deposited 3,4,9,10-perylene-tetracarboxylic dianhydride (PTCDA) based on organic p-i-n solar cells is investigated. Two different p-type materials were used: zinc phthalocyanine (ZnPc) and amine 4,4’, 4’’-tris{N,(3-methylphenyl)-N-phenylamino}-triphenylamine (m-MTDATA). It could be significant further improvements in power conversion efficiency by using the suitable p-type layer materials. Evidences showed that ZnPc is an apropos p-type material with match energy level. In addition, the broader spectral coverage of ZnPc is another key factor contributing to the higher photocurrent. It also possesses a shallow bulk trap level, providing more detrapping holes form the bulk trap states to highest occupied molecular orbital states for transporting in ZnPc. It is suggested that these are the main contributing factors to the superior photocurrent and high power conversion efficiency.
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Nguyen, Manh-Tan, and 阮錳新. "Effects of Screen-Printed Aluminum-Alloyed Front Emitter on Characteristics of Screen-Printed N-Type Mono-Crystalline Silicon Solar Cells." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/28z24k.
Full textAbstract:
碩士國立虎尾科技大學
光電與材料科技研究所
101
Effects of screen-printed aluminum-alloyed front emitter (AAFE) on characteristics of screen-printed N-type mono-crystalline silicon solar cells (SPNMSSC) were presented. The sheet resistance and the thickness of AAFE in SPNSSCs can be tuned by the firing temperature, the firing time, the waiting time, and the etching time of the KOH solution, respectively. The results show that the sheet resistance decreases from 250 to the 10 Ω/sq with increasing the firing time, respectively. On the other hand, the sheet resistance decreases with decreasing the waiting time. And with increasing etching time of the KOH solution, the sheet resistance of the Al-p+ was increased, and the thickness of the Al-p+ front surface field was decreased. Moreover, the larger thickness of the front surface field (FSF) can be achieved by increasing firing temperature and time. The optimum conversion efficiency can be obtained by suitably turned process parameters.
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Ji, Guan-Yu, and 紀冠宇. "Improved Photovoltaic Characteristics of Screen-Printed N-type Monocrystalline Silicon Solar Cells by Screen-Printed Diffusion and Laser Texturization Techniques." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/dvr3bx.
Full textAbstract:
碩士國立虎尾科技大學
光電與材料科技研究所
101
In this study, the Nd : YAG laser with a wavelength of 1064 nm was used to form various texturing patterns. The laser parameters include the power, the spacing of the laser line, the pattern, the frequency, and the speed of the laser. After laser pattern, the potassium hydroxide (KOH) solution was used to demonstrate various micro-grooved pyramids. The low reflection of surface and the high path of optical can be enhanced by the micro-grooved pyramids. Then, the screen-printed diffusion technique (SPDT) was adopted for fabrication simply and at low-cost solar cell applications. The conditions of SPDT include the squeegee speed, the emulsion thickness, the snap-off setting, the diffusion time, the gas flow, and the diffusion barrier layer. The better photovoltaic characteristics of the screen-printed mono-crystalline silicon solar cells can be demonstrated for tuning parameter of SPDT. Compared with the KOH texturing surface, the reflection of the surface with combined the laser and the KOH solution texturization can be reduced around 5-10 % at the laser power of 10 %, the frequency of 30 KHz, the line spacing of 100 ?m, and the speed of 800 mm/min. The sheet resistance of the emitter (p+) was obtained around 40-60 ohm/square at the diffusion time of 40-100 min, and nitrogen (N2) flow of 80 sccm. Furthermore, the sheet resistance of the base (n+) can be obtained around 12-14 ohm/square at the diffusion time of 40 min, nitrogen (N2) flow of 50 sccm, and different diffusion barrier layers. Finally, the screen-printed n-type mono-crystalline silicon solar cells with a conversion efficiency of 12.20 %, a open circuit voltage (Voc) of 557 mV, a short-circuit current density (Jsc) of 40.11 mA/cm2, and a fill factor (FF) of 0.55 can be demonstrated at the co-firing temperature of 870 ℃ for 35sec.
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Chu, Hsien-Min, and 朱涎民. "Improved Photovoltaic Characteristics of Screen-Printed N-Type Mono-Crystalline Silicon Solar Cells by Alkali Etching and Various Front Electrodes." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/5e465y.
Full textAbstract:
碩士國立虎尾科技大學
光電與材料科技研究所
102
The effects of KOH alkali etching and various electrode pastes on photovoltaic characteristics of screen-printed N-type mono-crystalline silicon solar cells (SPMSSCs) were presented. Firstly, the sheet resistances of the emitters in SPMSSCs were modified by KOH alkali etching after ohmic contact formation in the rear side of SPMSSCs. Furthermore, the P-type emitter in SPMSSCs can be obtained by the boron diffusion paste. The results reveal that compared with the SPMSSC without KOH alkali etching, the achievement of an conversion efficiency (CE) improvement of more than 3% absolute in the SPMSSC with KOH alkali etching was explored. Moreover, to investigate the effects of both front and rear electrodes on electrical characteristics of SPMSSCs, the Al, Ag, AgAl and AgB pastes were used as the front electrodes. On the other hand, the Ag pastes were used as the rear electrodes. The CE of 16.3% can be achieved by AgAl(6%) and Ag pastes as the front and rear electrode, respectively. The enhanced mechanisms could be due to the formation of front surface field (FSF) by the Al doped emitter and low bulk resistivity of Ag film for AgAl paste with around 4-6% Al doping.